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The City of Helsinki’s Building Control Services Archives are a repository for master drawings, working drawings and special plans.
Information on The City of Helsinki’s Map Service, the online permit service Lupapiste’s shop as well as the Karttakori service, the cabling information service and the Soili e-service.
You can apply for state subsidies for some construction and renovation projects, either as an interest-subsidised loan or a guaranteed loan. You need a favourable statement from the municipality to apply.
See here for the contact information of Building Control Services.